Lesson 8: Stars
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The Nearest Stars: a Guided Tour by Sherwood Harrington, Astronomical Society of the Pacific
www.astrosociety.org/uitc No. 5 - Spring 1986 © 1986, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. The Nearest Stars: A Guided Tour by Sherwood Harrington, Astronomical Society of the Pacific A tour through our stellar neighborhood As evening twilight fades during April and early May, a brilliant, blue-white star can be seen low in the sky toward the southwest. That star is called Sirius, and it is the brightest star in Earth's nighttime sky. Sirius looks so bright in part because it is a relatively powerful light producer; if our Sun were suddenly replaced by Sirius, our daylight on Earth would be more than 20 times as bright as it is now! But the other reason Sirius is so brilliant in our nighttime sky is that it is so close; Sirius is the nearest neighbor star to the Sun that can be seen with the unaided eye from the Northern Hemisphere. "Close'' in the interstellar realm, though, is a very relative term. If you were to model the Sun as a basketball, then our planet Earth would be about the size of an apple seed 30 yards away from it — and even the nearest other star (alpha Centauri, visible from the Southern Hemisphere) would be 6,000 miles away. Distances among the stars are so large that it is helpful to express them using the light-year — the distance light travels in one year — as a measuring unit. In this way of expressing distances, alpha Centauri is about four light-years away, and Sirius is about eight and a half light- years distant. -
Where Are the Distant Worlds? Star Maps
W here Are the Distant Worlds? Star Maps Abo ut the Activity Whe re are the distant worlds in the night sky? Use a star map to find constellations and to identify stars with extrasolar planets. (Northern Hemisphere only, naked eye) Topics Covered • How to find Constellations • Where we have found planets around other stars Participants Adults, teens, families with children 8 years and up If a school/youth group, 10 years and older 1 to 4 participants per map Materials Needed Location and Timing • Current month's Star Map for the Use this activity at a star party on a public (included) dark, clear night. Timing depends only • At least one set Planetary on how long you want to observe. Postcards with Key (included) • A small (red) flashlight • (Optional) Print list of Visible Stars with Planets (included) Included in This Packet Page Detailed Activity Description 2 Helpful Hints 4 Background Information 5 Planetary Postcards 7 Key Planetary Postcards 9 Star Maps 20 Visible Stars With Planets 33 © 2008 Astronomical Society of the Pacific www.astrosociety.org Copies for educational purposes are permitted. Additional astronomy activities can be found here: http://nightsky.jpl.nasa.gov Detailed Activity Description Leader’s Role Participants’ Roles (Anticipated) Introduction: To Ask: Who has heard that scientists have found planets around stars other than our own Sun? How many of these stars might you think have been found? Anyone ever see a star that has planets around it? (our own Sun, some may know of other stars) We can’t see the planets around other stars, but we can see the star. -
100 Closest Stars Designation R.A
100 closest stars Designation R.A. Dec. Mag. Common Name 1 Gliese+Jahreis 551 14h30m –62°40’ 11.09 Proxima Centauri Gliese+Jahreis 559 14h40m –60°50’ 0.01, 1.34 Alpha Centauri A,B 2 Gliese+Jahreis 699 17h58m 4°42’ 9.53 Barnard’s Star 3 Gliese+Jahreis 406 10h56m 7°01’ 13.44 Wolf 359 4 Gliese+Jahreis 411 11h03m 35°58’ 7.47 Lalande 21185 5 Gliese+Jahreis 244 6h45m –16°49’ -1.43, 8.44 Sirius A,B 6 Gliese+Jahreis 65 1h39m –17°57’ 12.54, 12.99 BL Ceti, UV Ceti 7 Gliese+Jahreis 729 18h50m –23°50’ 10.43 Ross 154 8 Gliese+Jahreis 905 23h45m 44°11’ 12.29 Ross 248 9 Gliese+Jahreis 144 3h33m –9°28’ 3.73 Epsilon Eridani 10 Gliese+Jahreis 887 23h06m –35°51’ 7.34 Lacaille 9352 11 Gliese+Jahreis 447 11h48m 0°48’ 11.13 Ross 128 12 Gliese+Jahreis 866 22h39m –15°18’ 13.33, 13.27, 14.03 EZ Aquarii A,B,C 13 Gliese+Jahreis 280 7h39m 5°14’ 10.7 Procyon A,B 14 Gliese+Jahreis 820 21h07m 38°45’ 5.21, 6.03 61 Cygni A,B 15 Gliese+Jahreis 725 18h43m 59°38’ 8.90, 9.69 16 Gliese+Jahreis 15 0h18m 44°01’ 8.08, 11.06 GX Andromedae, GQ Andromedae 17 Gliese+Jahreis 845 22h03m –56°47’ 4.69 Epsilon Indi A,B,C 18 Gliese+Jahreis 1111 8h30m 26°47’ 14.78 DX Cancri 19 Gliese+Jahreis 71 1h44m –15°56’ 3.49 Tau Ceti 20 Gliese+Jahreis 1061 3h36m –44°31’ 13.09 21 Gliese+Jahreis 54.1 1h13m –17°00’ 12.02 YZ Ceti 22 Gliese+Jahreis 273 7h27m 5°14’ 9.86 Luyten’s Star 23 SO 0253+1652 2h53m 16°53’ 15.14 24 SCR 1845-6357 18h45m –63°58’ 17.40J 25 Gliese+Jahreis 191 5h12m –45°01’ 8.84 Kapteyn’s Star 26 Gliese+Jahreis 825 21h17m –38°52’ 6.67 AX Microscopii 27 Gliese+Jahreis 860 22h28m 57°42’ 9.79, -
Tímaákvarðanir Á Myrkvum Valinna Myrkvatvístirna Og Þvergöngum Fjarreikistjarna, Árin 2017-2018, Og Fjarlægðamælingar
Tímaákvarðanir á myrkvum valinna myrkvatvístirna, þvergöngum fjarreikistjarna og fjarlægðamælingar, árin 2017—2018 Snævarr Guðmundsson 2019 Náttúrustofa Suðausturlands Litlubrú 2, 780 Höfn í Hornafirði Nýheimar, Litlubrú 2 780 Höfn Í Hornafirði www.nattsa.is Skýrsla nr. Dagsetning Dreifing NattSA 2019-04 10. apríl 2019 Opin Fjöldi síðna 109 Tímaákvarðanir á myrkvum valinna myrkvatvístirna, Fjöldi mynda 229 þvergöngum fjarreikistjarna og fjarlægðamælingar, árin 2017- 2018. Verknúmer 1280 Höfundur: Snævarr Guðmundsson Verkefnið var styrkt af Prófarkarlestur Þorsteinn Sæmundsson, Kristín Hermannsdóttir og Lilja Jóhannesdóttir Útdráttur Hér er gert grein fyrir stjörnuathugunum á Hornafirði á árabilinu 2017 til loka árs 2018. Í flestum tilfellum voru viðfangsefnin óeiginlegar breytistjörnur, aðallega myrkvatvístirni, en einnig var fylgst með nokkrum fjarreikistjörnum. Í mælingum á myrkvatvístirnum og fjarreikistjörnum er markmiðið að tímasetja myrkva og þvergöngur. Einnig er sagt frá niðurstöðum á nándarstjörnunni Ross 248 og athugunum á lausþyrpingunni NGC 7790 og breytistjörnum í nágrenni hennar. Markmið mælinga á nándarstjörnu og lausþyrpingum er að meta fjarlægðir eða aðra eiginleika fyrirbæranna. Að lokum eru kynntar athuganir á litrófi nokkurra bjartra stjarna. Í samantektinni er sagt frá hverju viðfangsefni í sérköflum. Þessi samantekt er sú þriðja um stjörnuathuganir sem er gefin út af Náttúrustofu Suðausturlands. Niðurstöður hafa verið sendar í alþjóðlegan gagnagrunn þar sem þær, ásamt fjölda sambærilegra mæligagna frá stjörnuáhugamönnum, eru aðgengilegar stjarnvísindasamfélaginu. Hægt er að sækja skýrslur um stjörnuathuganir á vefslóðina: http://nattsa.is/utgefid-efni/. Lykilorð: myrkvatvístirni, fjarreikistjörnur, breytistjörnur, lausþyrpingar, ljósmælingar, fjarlægðir stjarna, litróf stjarna. ii Tímaákvarðanir á myrkvum valinna myrkvatvístirna, þvergöngum fjarreikistjarna og fjarlægðamælingar, árin 2017-2018. — Annáll 2017-2018. Timings of selected eclipsing binaries, exoplanet transits and distance measurements in 2017- 2018. -
Temperature-Spectral Class-Color Index Relationships for Main
ASTRONOMY SURVIVAL NOTEBOOK Stellar Evolution SESSION FOURTEEN: THE EVOLUTION OF STARS Approximate Characteristics of Several Types of MAIN SEQUENCE STARS Mass in Contraction Surface Luminosity M Years on Radius Class Comparison to Zero Age Temp. compared Absolute Main in to Sun Main Sequence (K) to sun Magnitude Sequence suns Not well known O6 29.5 10 Th 45,000 140,000 -4.0 2 M 6.2 mid blue super g O9 22.6 100 Th 37,800 55,000 -3.6 4 M 4.7 late blue super g B2 10.0 400 Th 21,000 3,190 -1.9 30 M 4.3 early B5 5.46 1 M 15,200 380 -0.4 140 M 2.8 mid A0 2.48 4 M 9,600 24 +1.5 1B 1.8 early A7 1.86 10 M 7,920 8.8 +2.4 2 B 1.6 late F2 1.46 15 M 7,050 3.8 +3.8 4 B 1.3 early G2 1.00 20 M 5,800 1.0 +4.83 10 B 1.0 early sun K7 0.53 40 M 4,000 0.11 +8.1 50 B 0.7 late M8 0.17 100 M 2,700 0.0020 +14.4 840B 0.2 late minimum 2 Jupiters Temperature-Spectral Class-Color Index Relationships for Main-Sequence Stars Temp 54,000 K 29,200 K 9,600 K 7,350 K 6,050 K 5,240 K 3,750 K | | | | | | | Sp Class O5 B0 A0 F0 G0 K0 M0 Co Index (UBV) -0.33 -0.30 -0.02 +0.30 +0.58 +0.81 +1.40 1. -
A Joint ESA-CONSTELLATION Workshop on the Formation of Brown Dwarfs
-ESA- Space Science Faculty Courtesy NASA/JPL-Caltech CONSTELLATION is a European Commission Sixth Framework Marie Curie Research Training Network (contract number MRTN-CT-2006-035890) A joint ESA-CONSTELLATION workshop on the formation of brown dwarfs Contact info: [email protected]! www.rssd.esa.int/BD2009 Gemini Observatory/AURA WORKSHOP Recipes for making brownies: theory vs. observations Scientific Rationale: The origin of Brown Dwarfs (BDs) is an important component of the theory of star formation. Recent ground based and satellite observations are revealing an increasing number of BDs; however, their origin remains somewhat mysterious as their mass is 2 orders of magnitude below the average Jeans mass in star-forming clouds. Explaining why they are so common thus requires detailed understanding of the fragmentation processes during star formation, as well as exploring other formation scenarios. This workshop will focus on recent theoretical and observational progresses in the field of BD formation as well as explore current and future perspectives. Our purpose is to bring together the leading experts working in this field, foster new collabora- tions and, in particular, promote extended interactions among young PhD/post-doc researchers. SOC: L. Spezzi (chair, ESTEC) B. Mer´ın(ESAC) D. Stamatellos (University of Cardiff) V. Konyves (CEA/Saclay,SAp) C. Alves de Oliveira (LAOG, Grenoble) LOC: L. Spezzi (co-chair) J. Walcher (co-chair) G. Beccari Program: 9 September 2009 08:30 - 10:00 Registration + Coffee 10:00 - 10:15 Opening 10:15 - 11:00 I. Bonnell, BD formation, an introductory review Session 1: Observations of BDs Chairman: E. Mouraux 11:00 - 11:30 K. -
Monday, November 13, 2017 WHAT DOES IT MEAN to BE HABITABLE? 8:15 A.M. MHRGC Salons ABCD 8:15 A.M. Jang-Condell H. * Welcome C
Monday, November 13, 2017 WHAT DOES IT MEAN TO BE HABITABLE? 8:15 a.m. MHRGC Salons ABCD 8:15 a.m. Jang-Condell H. * Welcome Chair: Stephen Kane 8:30 a.m. Forget F. * Turbet M. Selsis F. Leconte J. Definition and Characterization of the Habitable Zone [#4057] We review the concept of habitable zone (HZ), why it is useful, and how to characterize it. The HZ could be nicknamed the “Hunting Zone” because its primary objective is now to help astronomers plan observations. This has interesting consequences. 9:00 a.m. Rushby A. J. Johnson M. Mills B. J. W. Watson A. J. Claire M. W. Long Term Planetary Habitability and the Carbonate-Silicate Cycle [#4026] We develop a coupled carbonate-silicate and stellar evolution model to investigate the effect of planet size on the operation of the long-term carbon cycle, and determine that larger planets are generally warmer for a given incident flux. 9:20 a.m. Dong C. F. * Huang Z. G. Jin M. Lingam M. Ma Y. J. Toth G. van der Holst B. Airapetian V. Cohen O. Gombosi T. Are “Habitable” Exoplanets Really Habitable? A Perspective from Atmospheric Loss [#4021] We will discuss the impact of exoplanetary space weather on the climate and habitability, which offers fresh insights concerning the habitability of exoplanets, especially those orbiting M-dwarfs, such as Proxima b and the TRAPPIST-1 system. 9:40 a.m. Fisher T. M. * Walker S. I. Desch S. J. Hartnett H. E. Glaser S. Limitations of Primary Productivity on “Aqua Planets:” Implications for Detectability [#4109] While ocean-covered planets have been considered a strong candidate for the search for life, the lack of surface weathering may lead to phosphorus scarcity and low primary productivity, making aqua planet biospheres difficult to detect. -
W359 E31 RS.Pdf
WOLF 359 "SÉCURITÉ" by Gabriel Urbina (Writer's Note: The following takes place on Day 864 of the Hephaestus Mission) INT. U.S.S. URANIA - FLIGHT DECK - 1400 HOURS We come in on the STEADY HUM of a ship's engine. There's various BEEPS and DINGS from a control console. Sharp-eared listeners might notice that things sound considerably sleeker and smoother than what we're used to. Someone TYPES into a console, and hits a SWITCH. There's a discrete burst of STATIC, followed by - JACOBI Sécurité, sécurité, sécurité. U.S.S. Hephaestus Station, this is the U.S.S. Urania. Be advised that we are on an intercept vector. Request you avoid any course corrections or exterior activity. Please advise your intentions. He hits a BUTTON. For a BEAT he just awaits the reply. JACOBI (CONT'D) Still no reply, sir. You really think someone's alive in there? I mean... look at that thing. It's only duct tape and sheer stubbornness keeping it together. KEPLER No. They're there. Rebroadcast, and transmit the command authentication codes. JACOBI Aye-aye. (hits the radio switch) Sécurité, sécurité, sécurité. U.S.S. Hephaestus, this is the U.S.S. Urania. I say again: we are on an approach vector to your current position. Authentication code: Victor-Uniform-Lima-Charlie- Alpha-November. Please advise your intentions. BEAT. And then - KRRRCH! MINKOWSKI (over radio receiver) U.S.S. Urania, this is Hephaestus Actual. Continue on current course, and use vector zero one decimal nine for your final approach. 2. JACOBI Copy that, Hephaestus Actual. -
The Search for Exomoons and the Characterization of Exoplanet Atmospheres
Corso di Laurea Specialistica in Astronomia e Astrofisica The search for exomoons and the characterization of exoplanet atmospheres Relatore interno : dott. Alessandro Melchiorri Relatore esterno : dott.ssa Giovanna Tinetti Candidato: Giammarco Campanella Anno Accademico 2008/2009 The search for exomoons and the characterization of exoplanet atmospheres Giammarco Campanella Dipartimento di Fisica Università degli studi di Roma “La Sapienza” Associate at Department of Physics & Astronomy University College London A thesis submitted for the MSc Degree in Astronomy and Astrophysics September 4th, 2009 Università degli Studi di Roma ―La Sapienza‖ Abstract THE SEARCH FOR EXOMOONS AND THE CHARACTERIZATION OF EXOPLANET ATMOSPHERES by Giammarco Campanella Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Our knowledge of extrasolar planets has grown exponentially, from our understanding of their formation and evolution to the development of different methods to detect them. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. The structure of the thesis is as follows. In Chapter 1 an historical background is provided and some general aspects about ongoing situation in the research field of extrasolar planets are shown. In Chapter 2, various detection techniques such as radial velocity, microlensing, astrometry, circumstellar disks, pulsar timing and magnetospheric emission are described. A special emphasis is given to the transit photometry technique and to the two already operational transit space missions, CoRoT and Kepler. -
The Photosphere and Circumstellar Environment of the Be Star Achernar
New windows on massive stars: asteroseismology, interferometry, and spectropolarimetry Proceedings IAU Symposium No. 307, 2014 c International Astronomical Union 2015 G.Meynet,C.Georgy,J.H.Groh&Ph.Stee,eds. doi:10.1017/S1743921314006905 The photosphere and circumstellar environment of the Be star Achernar Daniel M. Faes1,2, Armando Domiciano de Souza2,AlexC.Carciofi1 and Philippe Bendjoya2 1 Instituto de Astronomia, Geof´ısica e Ciˆencias Atmosf´ericas, Universidade de S˜ao Paulo, Rua do Mat˜ao 1226, Cidade Universit´aria, 05508-900, S˜ao Paulo, SP, Brazil email: [email protected] 2 Lab. J.-L. Lagrange, UMR 7293 - Observatoire de la Cˆote d’Azur (OCA), Univ. de Nice-Sophia Antipolis (UNS), CNRS, Valrose, 06108 Nice, France Abstract. Achernar is a key target to investigate high stellar rotation and the Be phenonemon. It is also the hottest star for which detailed photospheric information is available. Here we report our results to determine the photospheric parameters of Achernar and evaluate how the emission of a Viscous Decretion Disk (VDD) around it would be observable. The analysis is based on interferometric data (PIONIER and AMBER at ESO-VLTI), complemented by spectroscopy and polarimetry for the circumstellar emission. For the first time fundamental parameters of a Be photosphere were determined. The presence of a residual disk at the quiescent phase and some characteristics of the new formed disk (2013 activity) are also discussed. This is rare opportunity to precisely determine the stellar brightness distribution and evaluate the evolution of a just formed Be disk. Keywords. stars: individual (Achernar), stars: fundamental parameters, techniques: interfero- metric, circumstellar matter, stars: emission-line, Be 1. -
2021 Solar Rituality and Ephemerides
HE LANETARY YSTEM T P S Ideas, Formulas and Forms for a new Culture/Civilization 2021 SOLAR RITUALITY AND EPHEMERIDES (December 2020) [email protected] 1 2021 SOLAR RITUALITY AND EPHEMERIDES A rhythmic and ritual coordination and sowing for a planetary Order The TPS solar Sowing Ia, Fa a F a C a Ca intends to a a a" a aa " a ba a " the cyclic pulsations of the higher Creators, the planetary, solar and cosmic Entities: the conscious Dream of a New Culture and Civilization, as a manifestation on Earth of the evolutionary Plan and of a new human planetary Order.1 By working we learn to work, and in this Workshop of spatial Thought we learn together to build more and more knowingly Harmonic Thought-forms, as a result of a right or heavenly way of being and existing, in order to set up a better Future and to progressively release our humanity from its lower trammels. Humanity can and has to spread, in an impersonal and disinterested way, Seeds or Ideas capable of fertilizing consciousness making it resound to infinity: "Culture is a treasure of consciousness, therefore the field of the sowing of the new Thought is the human consciousness ... It is a vast field like Heaven: no one knows its boundaries. Thus the seeds to be spread have no number or form ... Only with formless seeds an infinite field can be cultivated. And the soil of human consciousness is ready to welcome them: many signs prove it, both above and below, and sowing cannot be deferred". -
The Spinning-Top Be Star Achernar from VLTI-VINCI
A&A 407, L47–L50 (2003) Astronomy DOI: 10.1051/0004-6361:20030786 & c ESO 2003 Astrophysics The spinning-top Be star Achernar from VLTI-VINCI A. Domiciano de Souza1,P.Kervella2,S.Jankov3,L.Abe1, F. Vakili1,3,E.diFolco4, and F. Paresce4 1 Laboratoire Univ. d’Astroph. de Nice (LUAN), CNRS UMR 6525, Parc Valrose, 06108 Nice Cedex 02, France 2 European Southern Observatory (ESO), Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago 19, Chile 3 Observatoire de la Cˆote d’Azur, D´epartement FRESNEL, CNRS UMR 6528, Boulevard de l’Observatoire, Letter to the Editor BP 4229, 06304 Nice, France 4 European Southern Observatory (ESO), Karl-Schwarzschild str. 2, 85748 Garching, Germany Received 5 May 2003 / Accepted 22 May 2003 Abstract. We report here the first observations of a rapidly rotating Be star, α Eridani, using Earth-rotation synthesis on the Very Large Telescope (VLT) Interferometer. Our measures correspond to a 2a/2b = 1.56 0.05 apparent oblate star, 2a and 2b being the equivalent uniform disc angular diameters in the equatorial and polar direction. Considering± the presence of a circum- stellar envelope (CSE) we argue that our measurement corresponds to a truly distorted star since α Eridani exhibited negligible Hα emission during the interferometric observations. In this framework we conclude that the commonly adopted Roche approx- imation (uniform rotation and centrally condensed mass) should not apply to α Eridani. This result opens new perspectives to basic astrophysical problems, such as rotationally enhanced mass loss and internal angular momentum distribution. In addition to its intimate relation with magnetism and pulsation, rapid rotation thus provides a key to the Be phenomenon: one of the outstanding non-resolved problems in stellar physics.